Regulation of Nucleotide Excision Repair by Proteolysis

蛋白水解调节核苷酸切除修复

• 批准号: 7073492
• 负责人: Pengbo Zhou
• 金额: $ 33.14万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7073492
• 关键词: DNA binding protein; DNA damage; DNA repair; epitope mapping; flow cytometry; gel mobility shift assay; gene expression; immunoprecipitation; ligase; molecular shape; nucleotides; phosphorylation; protein protein interaction; protein tyrosine kinase; proteolysis; ubiquitin; western blottings

DESCRIPTION (provided by applicant): Nucleotide excision repair (NER) plays an important role in maintaining genomic integrity through removing helix-distorting DNA damages caused by UV irradiation or chemical mutagens. Defects in NER underlie the human hereditary disease, xeroderma pigmentosum, which is characterized as sensitivity to ultraviolet light and a high incidence of skin cancer. Studies of NER have been focused on identifying components and the biochemistry of excision and repair reactions, while little is known about the regulatory mechanisms cells employ to control the NER activity. The Cullin 4A ubiquitination machinery has recently been shown to mediate ubiquitin-dependent proteolysis of the p48 subunit of damaged DNA binding proteins that are believed to participate in the initial DNA damage recognition step of NER. Our long-range goal is to understand how the ubiquitin-proteolytic pathway regulates NER, and to relate this understanding to human diseases associated with defective NER as well as the malfunctions of the ubiquitination machinery. The objective of this application is to understand the molecular basis, the regulatory pathways, and the functional significance of CUL-4A-mediated p48 degradation in controlling the damage-sensing step of nucleotide excision repair. The central hypothesis of the application is that the CUL-4A ubiquitination machinery controls the ability of the NER machinery to recognize and remove specific DNA damages through restricting the abundance of p48. The specific aims proposed are (1) To determine the molecular basis for CUL- 4A/DDB interactions and for subcellular distribution of DDB proteins. (2) To determine the functional significance of CUL-4A in DNA damage recognition and repair. (3) To assess the role of c-Abl in regulating p48 degradation and nucleotide excision repair. The results of this work will provide a new paradigm for the regulation of nucleotide excision repair by ubiquitin-dependent proteolysis, and generate a better understanding of the biochemical mechanisms controlling the intracellular distribution and abundance of DDB proteins. Completion of the proposed studies will also shed light on how abnormal activation of CUL- 4A contributes to tumor development.

描述（由申请人提供）：核苷酸切除修复（NER）通过消除由紫外线照射或化学诱变剂引起的螺旋扭曲 DNA 损伤，在维持基因组完整性方面发挥着重要作用。 NER 的缺陷是人类遗传性疾病着色性干皮病的基础，该疾病的特点是对紫外线敏感和皮肤癌的高发病率。 NER 的研究主要集中于识别切除和修复反应的成分和生物化学，而对于细胞用于控制 NER 活性的调节机制知之甚少。 Cullin 4A 泛素化机制最近被证明可以介导受损 DNA 结合蛋白 p48 亚基的泛素依赖性蛋白水解，这些蛋白被认为参与 NER 的初始 DNA 损伤识别步骤。我们的长期目标是了解泛素蛋白水解途径如何调节 NER，并将这种理解与与 NER 缺陷相关的人类疾病以及泛素化机制的故障联系起来。本申请的目的是了解 CUL-4A 介导的 p48 降解的分子基础、调节途径以及在控制核苷酸切除修复的损伤感知步骤中的功能意义。该申请的中心假设是，CUL-4A 泛素化机制通过限制 p48 的丰度来控制 NER 机制识别和消除特定 DNA 损伤的能力。提出的具体目标是 (1) 确定 CUL-4A/DDB 相互作用和 DDB 蛋白的亚细胞分布的分子基础。 (2)确定CUL-4A在DNA损伤识别和修复中的功能意义。 (3)评估c-Abl在调节p48降解和核苷酸切除修复中的作用。这项工作的结果将为通过泛素依赖性蛋白水解调节核苷酸切除修复提供新的范例，并更好地理解控制 DDB 蛋白的细胞内分布和丰度的生化机制。拟议研究的完成还将揭示 CUL-4A 的异常激活如何促进肿瘤的发展。